1 /*
2  * Copyright 2016 Google Inc.
3  *
4  * Use of this source code is governed by a BSD-style license that can be
5  * found in the LICENSE file.
6  */
7 
8 #include "Fuzz.h"
9 #include "SkString.h"
10 #include "SkParsePath.h"
11 
12 #include <stdlib.h>
13 
14 // Most of this is taken from random_parse_path.cpp and adapted to use the Fuzz
15 // instead of SKRandom
16 
17 static const struct Legal {
18     char fSymbol;
19     int fScalars;
20 } gLegal[] = {
21     { 'M', 2 },
22     { 'H', 1 },
23     { 'V', 1 },
24     { 'L', 2 },
25     { 'Q', 4 },
26     { 'T', 2 },
27     { 'C', 6 },
28     { 'S', 4 },
29     { 'A', 4 },
30     { 'Z', 0 },
31 };
32 
33 static bool gEasy = false;  // set to true while debugging to suppress unusual whitespace
34 
35 // mostly do nothing, then bias towards spaces
36 static const char gWhiteSpace[] = { 0, 0, 0, 0, 0, 0, 0, 0, ' ', ' ', ' ', ' ', 0x09, 0x0D, 0x0A };
37 
add_white(Fuzz * fuzz,SkString * atom)38 static void add_white(Fuzz* fuzz, SkString* atom) {
39     if (gEasy) {
40         atom->append(" ");
41         return;
42     }
43     // Use a uint8_t to conserve bytes.  This makes our "fuzzed bytes footprint"
44     // smaller, which leads to more efficient fuzzing.
45     uint8_t reps;
46     fuzz->nextRange(&reps, 0, 2);
47     for (uint8_t rep = 0; rep < reps; ++rep) {
48         uint8_t index;
49         fuzz->nextRange(&index, 0, (int) SK_ARRAY_COUNT(gWhiteSpace) - 1);
50         if (gWhiteSpace[index]) {
51             atom->append(&gWhiteSpace[index], 1);
52         }
53     }
54 }
55 
add_some_white(Fuzz * fuzz,SkString * atom)56 static void add_some_white(Fuzz* fuzz, SkString* atom) {
57     for(int i = 0; i < 10; i++) {
58         add_white(fuzz, atom);
59     }
60 }
61 
add_comma(Fuzz * fuzz,SkString * atom)62 static void add_comma(Fuzz* fuzz, SkString* atom) {
63     if (gEasy) {
64         atom->append(",");
65         return;
66     }
67     add_white(fuzz, atom);
68     bool b;
69     fuzz->next(&b);
70     if (b) {
71         atom->append(",");
72     }
73     add_some_white(fuzz, atom);
74 }
75 
MakeRandomParsePathPiece(Fuzz * fuzz)76 SkString MakeRandomParsePathPiece(Fuzz* fuzz) {
77     SkString atom;
78     uint8_t index;
79     fuzz->nextRange(&index, 0, (int) SK_ARRAY_COUNT(gLegal) - 1);
80     const Legal& legal = gLegal[index];
81     gEasy ? atom.append("\n") : add_white(fuzz, &atom);
82     bool b;
83     fuzz->next(&b);
84     char symbol = legal.fSymbol | (b ? 0x20 : 0);
85     atom.append(&symbol, 1);
86     uint8_t reps;
87     fuzz->nextRange(&reps, 1, 3);
88     for (int rep = 0; rep < reps; ++rep) {
89         for (int index = 0; index < legal.fScalars; ++index) {
90             SkScalar coord;
91             fuzz->nextRange(&coord, 0.0f, 100.0f);
92             add_white(fuzz, &atom);
93             atom.appendScalar(coord);
94             if (rep < reps - 1 && index < legal.fScalars - 1) {
95                 add_comma(fuzz, &atom);
96             } else {
97                 add_some_white(fuzz, &atom);
98             }
99             if ('A' == legal.fSymbol && 1 == index) {
100                 SkScalar s;
101                 fuzz->nextRange(&s, -720.0f, 720.0f);
102                 atom.appendScalar(s);
103                 add_comma(fuzz, &atom);
104                 fuzz->next(&b);
105                 atom.appendU32(b);
106                 add_comma(fuzz, &atom);
107                 fuzz->next(&b);
108                 atom.appendU32(b);
109                 add_comma(fuzz, &atom);
110             }
111         }
112     }
113     return atom;
114 }
115 
DEF_FUZZ(ParsePath,fuzz)116 DEF_FUZZ(ParsePath, fuzz) {
117     SkPath path;
118     SkString spec;
119     uint8_t count;
120     fuzz->nextRange(&count, 0, 40);
121     for (uint8_t i = 0; i < count; ++i) {
122         spec.append(MakeRandomParsePathPiece(fuzz));
123     }
124     SkDebugf("SkParsePath::FromSVGString(%s, &path);\n",spec.c_str());
125     if (!SkParsePath::FromSVGString(spec.c_str(), &path)){
126         SkDebugf("Could not decode path\n");
127     }
128 }
129